Patent Literature 1 describes a testing device for testing an encoder including: three terminals according to three types of encoders of a TTL (Transistor Transistor Logic) level system, an open collector system, and a line driver system; a plurality of LEDs which are connected to the three terminals, respectively; and a switch which is connected to the three terminals. In such a testing device, the switch located on the outside of a housing of the testing device is tilted to a position with which a type of the systems to be tested is associated, the switch is connected to the terminal associated with the type of the system to be tested and thus the LED associated with the type of systems to be tested is lit. Consequently, in accordance with Patent Literature 1, it is possible to quickly confirm which terminals is to be connected with a cable and test a performance of the encoder, thereby determining pass or fail the test.
Patent Literature 2 describes an encoder with a switch for switching an interface, the interface is configured by causing a collector of a transistor to connect to an output terminal as well as connect to a power supply terminal via a switch and a resistor, and causing an emitter of the transistor to connect to a GND terminal to output an encoder signal, and a switching piece of the switch provided at the rear end of a case is tilted to a left side or a right side to open and close the switch. Consequently, in accordance with Patent Literature 2, a function of the interface is altered either for the open collector system or for the TTL system with one encoder.